Investigation of magnetic excitation in Ca2Ru0.95Sn0.05O4

We propose to investigate the magnetic excitation spectrum of Ca2RuO4 lightly substituted with Sn, specifically Ca2Ru0.95Sn0.05O4, using inelastic neutron scattering. The parent compound Ca2RuO4 is a spin orbit coupled Mott insulator exhibiting antiferromagnetic order at 110 K and a well-defined magnon dispersion with a bandwidth of ~40 meV. In our recent publication (PHYSICAL REVIEW B 113, 054433 (2026)), we found that adding Sn to the Ru site changes the structure, pushing the system into a different strain state and altering how the magnetic moments are tilted compared to the original compound. We expect these structural changes to impact the magnetic exchange interactions and, consequently, the magnetic excitation spectrum.

To address this question, we propose inelastic neutron scattering measurements at 5 K using incident neutron energies of 80 meV and 20 meV. We plan to take measurements at 5 K using neutron energies of 80 meV and 20 meV, focusing first on 80 meV for 5 hours to fully map the magnon dispersion, and then using 20 meV to look at the low-energy excitations if possible (not necessary).

By comparing the dispersion of Ca2Ru0.95Sn0.05O4 with that of the parent compound, we aim to determine how orthorhombic strain and modified spin canting influence the magnetic exchange interactions. This measurement will show how changes in structure, magnetic direction, and exchange interactions work together in this spin-orbit coupled ruthenate system.